Recently, a display apparatus and a transmitting and receiving system have been developed each of which receives a wirelessly transmitted video signal and which displays an image that is based on the video signal. However, in cases where a radio wave is not normally received, an image may deteriorate in quality or may not be displayed at all. Such an image causes a viewer to feel uncomfortable. In light of this, a display apparatus is known which does not display an image whose quality is significantly deteriorated but which displays an image containing information indicating that the image is not receivable (Patent Document 1: Japanese Unexamined Patent Publication No. 352519/1992 (Tokukaihei 4-352519).
However, the display apparatus described in Patent Document 1 is arranged as follows. That is, the display apparatus compares a signal level of a received video signal with a predetermined level. When the signal level is less than the predetermined level, the display apparatus does not display the image that is based on the received video signal, but displays the image containing the information indicating that the image is not receivable. Incidentally, there are various reasons why the video signal cannot be normally received. The video signal cannot be normally received, for example, when a jamming radio wave or a different wireless communication device is present, or when the display apparatus is out of a communication range. In any case, the display apparatus of Patent Document 1 invariably displays the image containing the information indicating that the image is not receivable. This allows the viewer to know that the image is not receivable. However, the viewer does not know a reason why the image is not receivable. This made it impossible for a viewer to consider and find a way of dealing with a case where the image is not receivable the term “jamming” does not refer to intentional interference with respect to a certain device, but refers to radio interference with another device using the same frequency.